System and method for generating power

ABSTRACT

An object of the present invention is to provide a method and a system for implementing the method so as to alleviate the disadvantages of a reciprocating combustion engine and gas turbine when generating power. The invention is based on the idea of arranging a combustion chamber ( 10 ) outside a turbine ( 22 ) and providing compressed air from serially connected compressors to an air chamber in which the air is heated and then exhausted to the combustion chamber in order to carry out a combustion process supplemented with high pressure steam pulses.

FIELD OF THE INVENTION

The present invention relates to a method of generating power and topower generating system.

BACKGROUND OF THE INVENTION

In a gas turbine the first zone is exposed to temperature produced in acombustion chamber. Temperature of input gas to the gas turbinetherefore restricts efficiency of the gas turbine. In a piston enginecombustion is periodic which allows use of very high temperatures duringcombustion. However the reciprocating pistons and crank mechanismrestrict running speed of a piston engine.

A typical engine system of the prior art consists of a fuel tank and acombustion engine. An internal combustion engine comprises a set ofcylinders with a corresponding set of reciprocating pistons. One of theproblems associated with the above arrangement is that the movingpistons and other moving parts have to be constantly lubricated with oilwhich has a significant impact on running temperature of the combustionengine. Consecutively, the running temperature is a significant factorwhen considering the efficiency. The moving parts require constantlubrication and thus the above mentioned engine withstands runningtemperature of less than 100 degrees Celsius without a significantdeterioration of durability. Large portion of the produced heat is wasteheat which in relatively low temperature which in turn makes itdifficult to utilize the waste heat for energy production or otherpurposes.

U.S. Pat. 2,095,984 (H. Holzwarth) discloses an explosion turbine plant.The explosion turbine plant comprises an impulse rotor, pistonlessexplosion chambers for generating explosion gases and nozzles forexpanding and directing the gases to a rotor being driven exclusively byintermittent puffs of said gases.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is thus to provide a method and asystem for implementing the method so as to alleviate the abovedisadvantages. The objects of the invention are achieved by a method anda system which are characterized by what is stated in the independentclaims. The preferred embodiments of the invention are disclosed in thedependent claims.

The invention is based on the idea of arranging a combustion chamberoutside a gas turbine and providing compressed air to the combustionchamber in order to carry out a combustion process in controlled andoptimal conditions and use residue heat from the process. An air chamberis arranged between compressors and combustion chamber for exhaustingheated and compressed air into the combustion chamber.

An advantage of the method and system of the invention is that thecontrolled combustion process enables timed cyclical combustion whichproduces high average temperature. Pistons and crank mechanism are notneeded. During the timed cyclical combustion pressure rises whichreduces need for raising the pressure with a compressor which would needmechanical energy. According to the present invention, heat is exhaustedfrom the system in relatively high temperature similar to a typical gasturbine. This high temperature exhaust creates favourable conditions forutilizing the exhaust heat.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail bymeans of preferred embodiments with reference to the attached drawings,in which

FIG. 1 illustrates a first electric generator system according to anembodiment of the invention;

FIG. 2 illustrates a second electric generator system with steamcirculation system according to an embodiment of the invention;

FIG. 3 illustrates a third electric generator system with an injector orejector system according to an embodiment of the invention;

FIG. 4 illustrates a detail of a system having two combustion chambers;

FIG. 5 illustrates the changes in pressure over time in a systemaccording to an embodiment; and

FIG. 6 illustrates use of various available energy sources within thecombustion chamber according to an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Referring to a simple example of FIG. 1, the power generator systemcomprises a turbine 22 which is in connection with a power shaft 51 anda compressor 24 axially or via a transmission 20. The system may alsocomprise an electric generator which can be driven with the power shaft51 or it may also be axially connected to the turbine 22. A rotor of theturbine 22 rotates when energy is fed to the turbine by means of fluidflowing through the turbine. Rotation of the turbine rotor drives thetransmission 20 and the power shaft 51 and the compressor 24 which bothare connected to the transmission. The turbine, the generator, the powershaft and the compressor may be connected to the transmission by meansof drive shafts, axles or other suitable power transmission means. Thearrangement converts the energy fed to the turbine 22 into mechanicalwork of the power shaft 51 and into air pressure with the compressor 24which compresses air for the combustion chamber 10. In an embodiment thecompressor 24 accumulates compressed air into an air tank 32 which thenfeeds the combustion chamber 10 with the compressed air accumulated inthe air tank 32. The compressor 24 is preferably a screw compressorwhich is highly efficient and able to provide high pressure to thecombustion chamber 10 and to the air tank 32. In an embodiment, thesystem comprises a second screw compressor connected in series with thefirst screw compressor 24 to provide even higher pressure to the airtank. In an embodiment, the system comprises a combination of an axialcompressor 24, such as a radial compressor and a screw compressorconnected in series with the axial compressor 24 to provide air to theair tank. One or more or all of the compressors can be for exampleaxial, radial, screw, piston or some other type of compressor. Theseries of compressors can be a combination of one or more of saidcompressor types connected in parallel or in series. The compressor orthe compressors are preferably arranged to build up pressure of over 2MPa to the air tank. In an embodiment, the compressor or the compressorsare arranged to build up pressure of over 3 MPa, 3.5 MPa or 4 MPa to theair tank. In an embodiment the compressor 24 may be driven with anelectric motor. In an embodiment an intercooler can be provided betweenthe series-connected first compressor and the second compressor to cooldown the air between the compressors. In an embodiment intercoolers canbe provided between some or all of the series-connected compressorstages to cool down the air between the compressors. The intercooler canthen be used to generate steam which can be injected into the combustionchamber in a form of short, high pressure steam pulses between expansionphases of the combustion cycle. In an embodiment serially connectedscrew compressors can share a common shaft so that successivecompression stages are partitioned along the common shaft andintercoolers are provided between each compression stages to extractheat from the compressed gas. Compressed air from any compression stagecan be directed to flow into a combustion chamber 10, air chamber 27,air tank 32 or some other part of the system. Preferably the combustioninside the combustion chamber is deflagration combustion, not detonatingcombustion. Detonating combustion is an unwanted phenomenon as thepressure tends to rise to levels which can damage the system, especiallycontrolled valves. Deflagration combustion is fundamentally differentfrom detonation combustion which is unwanted in the context of thepresent power generating system.

The electric generator system also comprises a combustion chamber 10which is arranged to receive compressed air from the compressor 24, airchamber or from the air tank 32 and fuel from a fuel tank 30 to initiatea combustion process. The compressed air is released from the air tankinto the combustion chamber 10 by means of a controllable valve. Thecompressed air is preheated before entering the combustion chamber witha heat recovery unit 40 which conveys heat from the combustion chamberto the compressed air. A regenerator can be used after the lastcompressor to heat up the compressed air before it is fed to thecombustion chamber or to a by-pass duct which bypasses the combustionchamber. The regenerator may use waste heat from e.g. exhaust gas orcombustion chamber for heating up the compressed air. The compressed airmay also be preheated with other means, for example electrically with aresistor, when the system is started and the combustion chamber is atroom temperature.

In an embodiment one or more air chambers 27 each comprising a cylinderdefining a volume inside it and a movable piston for changing the volumeinside the cylinder, the volume being defined by the cylinder and thepiston. The cylinder comprises input and output for air and said inputand output are preferably controlled by one or more valves. The pistonpreferably comprises a valve, such as a clap valve or a flap valve, forenabling a flow of air in to the space defined by the cylinder and thepiston. The cylinder preferably comprises one or more air ducts on it orin its walls for heating or cooling the cylinder and its contents byrunning hot or cold air, respectively, through the one or more airducts. In this case hot air means hotter than the cylinder and cold airmeans colder than the cylinder. Compressed air from the compressor orfrom any stage of the serially connected compressors can be arranged toflow into the one or more air chambers. In an embodiment the systemcomprises one air chamber for each stage of serially connectedcompressors so that a flow of compressed air from each compressing stageis arranged to flow into a dedicated air chamber. In an embodiment theair pressure in a single air chamber can be raised gradually byarranging a flow of compressed air after each stage of seriallyconnected compressors to said air chamber.

The air chambers can be operated in steps which comprise cooling downthe air chamber, filling the air chamber gradually, heating up the airchamber and its contents, and finally, exhausting the compressed andheated air from the air chamber. The process repeats itself in a cyclehaving a certain cycle time. The heated air from the air chamber isexhausted preferably via heat exchanger to the combustion chamber. Theheat exchanger can be a part of the air chamber or in connection withthe air chamber. In an embodiment the air ducts of the cylinder of theair chamber form the heat exchanger.

The cooling step in the operation of the air chamber can be realized byarranging a flow of a fluid such as steam or ambient air or some othergas through the air chamber or through the air ducts of the air chamber.The cooling air can be in atmospheric pressure, i.e. approximately 100kPa. The cooling step may take for example 7.5% or 6 to 10% of the timeof the cycle, for example 9 seconds in a 120 second cycle.

In the filling step each air chamber is filled with air from dedicatedcompressing stage or in case of a single air chamber, it is graduallyfilled with air from one or more compressors until a desired pressurewithin the air chamber is reached. The input valve to the air chamber isopened and compressed air is arranged to flow into the air chamber. Thegradual filling is preferably achieved by arranging a flow of compressedair from more than one stage of serially connected compressors. Thedesired pressure may vary but it is higher than the atmosphericpressure. In an embodiment the desired pressure can be for example atleast 1.5 Mpa, 2 Mpa, 3 Mpa, 4 Mpa or some other pressure. The fillingstep may take for example less than 1% or 0.5 to 2% of the time of thecycle, for example 1 second in a 120 second cycle.

The heating step is realized by arranging a flow of hot air, e.g. from aheat exchanger, through the air ducts of the air chamber. The heating ofthe air chamber and thus the air within the air chamber furtherincreases the pressure of the air within the air chamber. The heatingstep may take for example 40% or 30 to 60% of the time of the cycle, forexample 50 seconds in a 120 second cycle.

In the exhausting step the output valve of the air chamber is opened andthe compressed and heated air is arranged to flow into the combustionchamber. Preferably the heated air flows through a heat exchanger 25before entering the combustion chamber. The exhausting of the compressedand heated air may be facilitated with the piston of the air chamber.The exhausting step may take for example 50% or 40 to 60% of the time ofthe cycle, for example 60 seconds in a 120 second cycle.

Fuel is released or pumped from the fuel tank and injected into thecombustion chamber or mixed with air before introduction to thecombustion chamber. The fuel is preferably diesel or liquid natural gas(LNG). In an embodiment, the fuel is gasoline, natural gas, ethanol,biodiesel or a mixture of two or more the preceding fuels. In anembodiment, the fuel comprises hydrogen and carbon monoxide mixturewhich is a by-product of a soda recovery unit. In an embodiment water orsteam may be injected with fuel into the combustion chamber. In anembodiment the fuel comprises coal dust or brown coal dust as such ormixed to natural gas, diesel or some other suitable fuel.

The fuel injected into the combustion chamber ignites due to highpressure and temperature inside the combustion chamber or it is ignitedby a dedicated ignition system. The high pressure in the combustionchamber is arranged by releasing air from the air tank to the combustionchamber. In addition to the preheating, the heat of the combustionchamber heats up the released air inside the combustion chamber andbuilds up even higher pressure. The ignition may be continuouslytriggered by a dedicated energy source or when the system is started andthe combustion chamber has not yet reached its running temperature. Thededicated energy source for ignition can be e.g. an ignition coil, acondenser, a pre-combustion chamber, a glow plug, a pre-glowarrangement, a heater arrangement, plasma ignition and laser ignition.In an embodiment the system comprises an antechamber or a pre-combustionchamber. A fuel mixture can be ignited in the pre-combustion chamber toinitiate the combustion process. The combustion process produces heatwhich heats up the combustion chamber and keeps the combustion processrunning by heating the fuel and the compressed air which are introducedinto the combustion chamber. In an embodiment the ignition is also usedduring the combustion cycle after the system is started. In anembodiment the heat recovery unit 40 or other means of heat extractionis used to convey heat from the combustion chamber or combustion processto water or steam and generate high pressure steam. The high pressuresteam is injected into the combustion chamber between the expansionphases of the combustion process. The steam is injected in short, highpressure pulses and the amount of pulses between two expansion phasesmay be for example 1 to 10, 2 to 8, 3 to 6 or some other amount, such as4, 5, 7 or 8.

In an embodiment the system comprises means, such as heat exchangers,for producing heat to a district heating system. Some of the thermalenergy that the electric generator system produces can be extracted fromthe system and transferred with heat exchanger to heating water of adistrict heating system. This combined production of electrical andthermal energy raises the overall efficiency of the system.

In an embodiment the system comprises means, such as heat exchangers,for using the thermal energy of the electric generator system to run anabsorption cooling system. Some of the thermal energy that the electricgenerator system produces can be extracted from the system andtransferred with heat exchanger to absorption cooling system which inareas of warm climate may raise the overall efficiency of the system.

The combustion chamber 10 is preferably a hollow container with inputmeans for fuel and compressed air and an output for combustion productsi.e. exhaust gas. The inputs and the output are controllable and may beclosed and opened in specific phases of a combustion cycle in order tobuild up pressure into the combustion chamber before the ignition of thefuel and to expel combustion products after the ignition, input andoutput can be understood as an inlet and an outlet, respectively, butthe terms input and output are used throughout this text. One or morevalves can be used to control flow to and from the combustion chamber.In an embodiment one or more of the input and/or output valves are socalled radial valves i.e. located radially around the combustion chambercover. The input valves can be fixed to an inclined position to thecombustion chamber i.e. not perpendicular to the combustion chamberwall. In an embodiment one or more input valves functionally connectedto the combustion chamber 10 for controlling the combustion process arefixed to an inclined position to the normal of the combustion chamberwall so that an input of gas produces a controlled whirl of gas to thecombustion chamber. The inclined position of a valve produces a whirl ofgas in the combustion chamber when the gas is injected through theinclined valve. This type of whirl can be controlled with the inclinedvalves whereas random whirls produced by perpendicularly positionedvalves are very difficult if not impossible to control. The input valvescan be used to control the whirl by selecting suitable inclinationangles and/or by timing openings of the valves. The combustion processin the combustion chamber is a cycle process which at least resemblesDiesel cycle. Preheated compressed air from the air tank is introducedinto the combustion chamber and fuel is injected into the combustionchamber until the air-fuel mixture ignites. The combustion of theair-fuel mixture expands its volume so the combustion products and thecompressed air are expelled through the output when output valve isopened. Running speed of the combustion cycle is controlled bycontrolling the input and output valves. The running speed may be chosenfreely within certain limits which are defined by the properties of thesystem. Such properties that may limit the running speed may be forexample operation speed of the valves, the air pressure in the air tank,fuel type, etc. However, the running speed may be adjusted for optimalperformance in each system because it is not restricted by movingpistons or similar physical limitations of moving mass.

The combustion chamber has preferably a simple form, most preferably asphere or a cylinder, for enabling a quick, clean and completecombustion process. The simple form enables higher running temperatureswhich increases efficiency and decreases the amount of harmful particlesand gases produced during the combustion process. The combustion chamberis arranged to function in high temperatures. In addition to the simpleform, also the material of the combustion chamber has to withstand hightemperatures without significant deterioration of performance ordurability. The material of the combustion chamber may be ceramic,metal, alloy or preferably a combination of two or more materials. Forexample, the combustion chamber may comprise an alloy encasing with aceramic inner coating. The alloy encasing withstands high pressure andstrong forces while the ceramic inner coating withstands high surfacetemperatures. The construction of the combustion chamber is preferablyarranged to withstand running temperature of 400 degrees of Celsius. Inan embodiment the combustion chamber is arranged to withstand runningtemperature of 500, 600, 700 or 800 degrees of Celsius or more. Thecombustion chamber itself does not comprise any moving parts so it isrelatively simple task to design the combustion chamber to withstandhigh temperatures. The moving parts that experience the highest thermalstress are the valves at the input and output ports of the combustionchamber. The input valves are not subjected to such high temperatures asthey are cooled during each inlet cycle by incoming air. However, thereare valves readily available that are designed to operate in thesetemperatures and therefore it should be relatively easy task to designand realize a durable valve system.

The output of the combustion chamber 10 leads a stream consisting of thecombustion products and the compressed air from the combustion chamberinto the turbine 22. Due to the high pressure in the combustion chamber,the stream is expelled with high velocity when the output is opened. Theexpelling of the combustion products may be enhanced by having theoutput and the air input open simultaneously for a certain period oftime. The turbine 22 comprises a rotor which rotates when the streamflows through the turbine. The rotating rotor drives the transmission 20which in turn drives the power shaft 51 and the compressor 24 as statedearlier. The stream is guided to exhaust pipe 90 after the turbine andthe exhaust gas 98 is released from the system. The power shaft 51provides the output of the system and it can be connected to e.g. adrivetrain of a vehicle or an electric generator for converting themechanical work into electric energy.

The combustion chamber 10 is preferably a separate unit outside theturbine 22. The combustion products expelled from the combustion chamber10 are guided to the turbine 22 with a pipe, tube or some other channelconnecting the combustion chamber 10 and the turbine 22. In anembodiment the system comprises multiple combustion chambers. In thatcase each combustion chamber has a pipe, tube or some other channelconnecting that combustion chamber to the turbine 22. Preferably themultiple combustion chambers are arranged to expel their combustionproducts sequentially, i.e. not all at the same time, to provide asteadier flow of combustion products to the turbine 22, in anembodiment, the steadier flow to turbine 22 is accomplished with short,high pressure steam pulses which are injected into the combustionchamber between the expansion phases of the combustion process. In anembodiment two or more combustion chambers are arranged to expel theircombustion products simultaneously in order to produce a high peak ofenergy to the turbine.

In an embodiment a generator driven by the power shaft 51 feeds anelectric storage system which comprises one or more capacitors, supercapacitors or batteries for storing the electrical energy produced bythe generator. This type of system can be us in vehicular applicationsfor producing and storing electrical energy for electrical motors of avehicle. Also in vehicular applications the system can comprise anadditional air tank or it may be connected to an air tank of the vehicleusing it as a hybrid air tank for two purposes. The additional air tankmay be filled with compressed air from a compressor of the electricgenerator system or a compressor of the vehicle. Energy from braking ofthe vehicle can be converted in to compressed air with the compressor ofthe vehicle and stored in to the additional air tank. The vehicle mayalso comprise an exhaust brake which can also be connected to theadditional air tank for increasing the pressure of the additional airtank. The compressed air of the additional air tank can be supplied tothe compressors of the electric generator system where the pressure ofthe air is increased to final desired level.

Now referring to FIG. 2, in an embodiment the power generator systemfurther comprises a generator 26 driven by the power shaft and a steamcirculation system. The power generator system having a generator iscalled an electric generator system. The steam circulation systemcomprises a steam tank 34, heat recovery unit 40, a heat exchanger 42, acondenser 50 and a water tank 36. In an embodiment, the steamcirculation system further comprises a second turbine. Water and steamcirculates in the steam circulation system wherein the water isaccumulated into the water tank 36 and the steam is accumulated into thesteam tank 34. In an embodiment the steam tank and the water tank is asingle tank wherein the water is accumulated in the bottom of the tankand steam is accumulated on the top of the tank. The flowing of thesteam is based on pressure differences within the system but it might beassisted with pumps or similar arrangement if necessary. The flowing iscontrolled by means of a number of valves which may be operated incontrolled manner.

The steam is arranged to flow from the steam tank 34 to the heatrecovery unit 40. The heat recovery unit 40 is in thermal connectionwith the combustion chamber 10 so that the combustion chamber heats upthe heat recovery unit in which the heat is conveyed to the steamflowing through the heat recovery unit. The heat recovery unit may be aseparate unit having a thermal connection to the combustion chamber orit may be a fixed part of the combustion chamber. In an embodiment theheat recovery unit may even a pipework inside the combustion chamber ortubing on the surface of the combustion chamber. When the heat from thecombustion chamber is conveyed to the steam flowing through the heatrecovery unit, the steam rapidly heats up and expands. The steam flow isthen directed to the turbine 22 wherein the steam flow rotates the rotorof the turbine 22 simultaneously with the combustion products andcompressed air which are expelled from the combustion chamber 10 intothe turbine 22.

In an embodiment a heat pump can be used to produce steam. Heat pumpsare known to be effective when needed temperature difference is small. Aheat pump is therefore a good alternative for adding thermal energy towater which is at or near its boiling point. For example an air-to-wateror water-to-water heat pump can be used for producing steam from waterthat is preheated to near or at its boiling point. The steam productioncan be assisted with other energy sources, including those alreadymentioned, in addition to the heat pump. In an embodiment steam ofexhaust flow is condensed into water and the heat released from thecondensing is used as a heat source for the heat pump. The temperaturewhere the condensing takes place depends on the pressure of the exhaustgas and steam. Said temperature is 100 degrees Celsius in atmosphericpressure but in higher pressure it can be for example as high as 200,300, 400 or even 500 degrees Celsius. The heat pump uses the heat tovaporize water for providing fresh steam to the system. In an embodimentheat provided by one or more intercoolers of the system is used as aheat source for the heat pump.

In an embodiment the heat recovery unit 40 is replaced with heatinsulating material and time-dependent steam injections to thecombustion chamber 10 maintain a stable running temperature of thecombustion chamber. The time-dependent steam injections are preferablyshort, high pressure steam pulses injected into the combustion chamberbetween expansion phases of the combustion process. The injected highpressure steam pulses need only a reduced amount of steam due to theirshort pulse type length. After injection the steam exits the combustionchamber and enters into the turbine 22.

In an embodiment the system comprises an additional burner forincreasing the amount and/or the temperature of the steam in the system.The burner preferably uses the same type of fuel as the rest of thesystem. The fuel is burned in the burner for producing heat which thenheats steam and/or the burning fuel heats water to produce steam. Theadditional burner can be used in systems which do not produce enough“waste heat” to produce an adequate amount of steam. The system is alsoadapted to use other external heat sources and thus heat as such orconverted into compressed air or steam can be input to the system fromexternal sources. The external source can use the same fuel or adifferent fuel than the combustion chamber of the system. Examples ofusable heat energy from external sources can be e.g. waste heat of aheavy machine process, waste heat of a vehicle's engine or brake system,geothermal energy, etc. In an embodiment where the system producesexcess heat, a portion of the heat produced by the system can beconverted in an external process e.g. in Rankine process or Stirlingprocess to mechanical work. The use of the additional burner ensuresthat a desired amount of steam in a desired temperature and pressure canbe achieved.

In an embodiment, the steam is not directed into the same turbine 22 asthe combustion products. In that embodiment the system comprises asecond turbine which is dedicated to the steam stream while the (first)turbine 22 is dedicated to the stream of combustion products andcompressed air. The stream of combustion products and compressed air mayeven be arranged to flow through an additional heat exchanger after theturbine 22 to heat up the steam stream before that stream enters thesecond turbine. The arrangement of the second turbine may be similar toknown combined cycle power plants.

From the turbine a stream of steam, compressed air and combustionproducts flows through the heat exchanger 42 to the condenser 50 whereinthe steam is condensed into water and the compressed air and thecombustion products are guided out of the system through exhaust pipe90. In the embodiment of the second turbine the stream of combustionproducts and compressed air is arranged to flow through heat exchanger42 directly to exhaust pipe and the steam stream is arranged to flowthrough the heat exchanger 42 and the condenser 50 to the water tank 36.

Condensing water from the exhaust flow may cause accumulation ofimpurities to the system which is undesirable. In an embodiment this issolved by feeding the condenser with fresh, atmospheric air from whichrelatively clean water can be condensed to the system.

The water condensed from the steam and/or from the atmospheric air flowsinto the water tank 36 or is pumped in there. An ion exchanger 52 may bearranged between the condenser 50 and the water tank 36 for purifyingthe water before it enters the cycle again. The water tank 36accumulates water which is then guided or pumped to the heat exchanger42. The heat exchanger conveys the heat from the stream of steam,compressed air and combustion products to the water flowing through theheat exchanger. The heat of the heat exchanger vaporizes the water intosteam which is then guided to flow back into the steam tank 34. From thesteam tank 34 the high pressure steam can be released in short bursts tocreate short, high pressure pulses to the combustion chamber.

FIG. 3 illustrates an electric generator system which is otherwisesimilar to the system of FIG. 2 except that the system further comprisesa pump having a converging-diverging nozzle, for example an injector orejector 12 for combining the stream of combustion products from thecombustion chamber 10 and the steam from the heat recovery unit 40 orfrom the heat exchanger 42 wherein the ejector 12 guides the steam andcombustion products into the turbine 22 for rotating the rotor of theturbine. The pump having a converging-diverging nozzle is called anejector within the description but in an embodiment the pump can also befor example an injector, steam injector or steam ejector. The ejector 12is between the turbine and the combustion chamber and its heat recoveryunit. The combustion products and the compressed air are expelled intothe ejector wherein the steam from the heat recovery unit is superheatedby the hot matter from the combustion chamber. The superheating of thesteam causes rapid expansion of the steam. The ejector 12 guides thestream of superheated steam, combustion products and compressed air intothe turbine 22 wherein the stream rotates the rotor of the turbine. Inan embodiment, short, high pressure steam pulses are injected into theejector 12 from where the steam flows to the turbine and rotates therotor or the turbine. In an embodiment an afterburner can be used in theejector 12 between the combustion chamber 10 and the turbine 22.However, the temperature of the exhaust gas has to be monitored andcontrolled since the input gas of the turbine should preferably have alow temperature and the afterburner rises the temperature of the exhaustgas. In an embodiment the afterburner is used intermittently and notcontinuously.

In an embodiment the system also comprises an adjustable nozzle and avalve in connection with the ejector 12 and the output of the combustionchamber 10 for adjusting the expelling of combustion products from thecombustion chamber 10. The nozzle has a certain design and a form whichmay be altered. The nozzle is within the ejector in a by-pass flow ofthe steam flowing from the heat recovery unit 40 to the turbine 22. Theform of the nozzle has a significant impact to the expelling of thecombustion products from the combustion chamber when the valve in theoutput is open. By altering the form of the nozzle the expelling of thecombustion products may be increased with help of the by-pass flow ofthe steam.

In an embodiment a portion of the combustion products, i.e. the exhaustgas, is guided to a low temperature/pressure region of the turbine 22 orto a low pressure turbine when the exhaust gas is exhaust from thecombustion chamber. An ejector or ejectors 14 a, 14 b can be omitted inthis embodiment since the pressure in suction side is higher than thepressure in low temperature/pressure region.

FIG. 4 illustrates a detail of an embodiment of a combustion systemhaving two combustion chambers 10 a and 10 b and an ejector 12. Thenumber of combustion chambers and ejectors is not limited to thisexample. Two combustion chambers and one ejector were chosen for thisembodiment to give an example and represent the capabilities of thesystem. In an embodiment the electric combustion system has one, two,three, four or more combustion chambers and zero, one, two, three, fouror more ejectors. In an embodiment the ejectors are not essential andthe system can operate without a single ejector.

Each combustion chamber 10 a, 10 b comprises one or more inputs 101, 102which can be controlled with or without input valves and one or moreoutputs 111, 112 which can be open or controlled with output valves. Theinputs and the outputs may be controlled without valves by controllingthe pressure of the inputs and outputs because gases tend to flow from ahigher pressure region to a lower pressure region. In an embodiment atleast some of the inputs and outputs are controlled with gas vibrationsor oscillations instead of valves. Movement of gas in a pipeline tendsto oscillate with a frequency or a plurality of frequencies which is/arespecific to the pipeline and the gas, so called eigenfrequencies. Thepulse action is created by the periodic combustion and fortified by theeigenfrequencies of the flow system. Specific oscillation frequenciescan be exploited by controlling the periodic combustion process to matchthe frequency of the specific gas oscillation so that these amplify eachother. In an embodiment the combustion cycle is matched with thespecific oscillation frequency of the compressed air flowing in thesystem. In an embodiment valve actuation is optimized to harmonize withthe desired periodical operation of the pulse turbine. In an embodimentthe combustion cycle, the specific oscillation frequency of thecompressed air flowing in the system and a specific oscillationfrequency of the steam flowing in the system are all matched to the samephase so that they amplify each other. The specific osculationfrequencies of the steam and the compressed air flows can be matchedwith pipeline design. In an embodiment the combustion cycle is matchedwith the specific oscillation frequency of the compressed air flowing inthe system and with the specific oscillation frequency of the steamflowing in the system but the specific frequencies of the steam and thecompressed air are not matched with each other. Preferably the flowsystem is optimized such that the flow losses are minimized.

In an embodiment the system comprises compressors connected in series toproduce high pressure compressed air to the combustion chamber. Atypical way is to feed compressed air from the first compressor to thesecond compressor and from the second compressor to the thirdcompressor, and so on. The pressure of the compressed air builds up ineach compressor stage and finally the compressed air from the lastcompressor of the series of compressors is released to the combustionchamber or to the air chamber. This is energy consuming as the amount(mass) of compressed air is the same in each compressing stage. Acompressing stage can be a single compressor or a number of compressorsin parallel connection i.e. each having common input and output. In anembodiment serially connected screw compressors can share a common shaftso that successive compression stages are partitioned along the commonshaft and intercoolers are provided between each compression stages toextract heat from the compressed gas. Compressed air from anycompression stage can be directed to flow into a combustion chamber 10,air chamber, air tank 32 or some other part of the system. In anembodiment a portion of the mass of the compressed air is released tothe combustion chamber and the remaining portion of the mass of thecompressed air is released to the following compressor in the series ofcompressors. The pressure within the combustion chamber rises graduallyas the compressed air is released to the combustion chamber betweencompressing stages. Heat can be extracted from the compressed airbetween the compressing stages by using one or more intercoolers. Alsothe amount of air to be compressed diminishes in subsequent compressingstages as part of the air is released to the combustion chamber betweenthe compressing stages. A plurality of pressure tanks can be used forstoring compressed air in various pressures between atmospheric pressureand the highest pressure from the last compressor. A further advantageis that the gradual air feeding allows the other inputs to be fed to thecombustion chamber during a desired pressure. For example the combustionchamber could first receive a first release of compressed air, then afuel input, then a second release of compressed air, then a steam inputand finally a third release of compressed air to a desired finalpressure. The order and timing of the inputs can be optimized based onthe system variables.

In an embodiment the combustion chamber is arranged to work in twoalternating cycles. The first cycle may be any of the combustion cycles,i.e. a topping cycle, where fuel is fed to the combustion chamber asdescribed within this document. The second cycle is a cooling cycle,i.e. a bottoming cycle, wherein the combustion chamber is cooled bymeans of arranging a flow of fluid, such as ambient air, steam or someother gas, through the combustion chamber. Cooling the combustionchamber transfers thermal energy from the combustion chamber to thefluid flowing through the combustion chamber and thus makes thecombustion chamber less warm. Both cycles may take an equal amount oftime. In an embodiment the first cycle is longer than the second cycleor the first cycle is shorter than the second cycle.

FIG. 6 illustrates an embodiment wherein the combustion chamber isarranged to work with various available energy sources in order toachieve a desired effect. Typical desired effects include fuel economyand temperature control and power control. For example, the turbine hasa temperature limit for input gas to protect the turbine but typicallyhigher combustion temperatures give better fuel economy. The turbineinput temperature limits the efficiency of the system when thecombustion chamber operates only with high temperature topping cycles. Avast supply of compressed air or steam from e.g. waste heat or externalsources enables use of higher combustion temperatures and pressures intopping cycles when the available air or steam can be used in bottomingcycles after topping cycles to lower the average input gas temperatureto the turbine. In FIG. 6 solid line illustrates pressure achieved withcombustion of fuel in topping cycle and dotted line illustrates pressureachieved with input of compressed air or steam to the combustion chamberin bottoming cycle. Cycles t_(c1), and t_(c5) are topping cycles inwhich fuel is combusted and t_(c2), t_(c3), t_(c4) and t_(c6) arebottoming cycles in which fuel is not combusted. In t_(c1) thecombustion of fuel is supplemented with short injections of compressedgas or steam after ignition of fuel. This enables use of highertemperatures in topping cycles and therefore results higher efficiencyand better fuel economy. If an external source generates plenty of heatwhich is converted into steam, the system can be run with the steam forextended periods of time without using any fuel during that period.Preferably the available energy from different sources is constantlymonitored with sensors and decision between topping cycle and bottomingcycle is preferably made each time based on e.g. available energysources and required power. The topping and bottoming cycles can be usedsimultaneously, with a phase difference to each other, in alternatingorder or following a pattern. This can be achieved with control hardwareand software well known in the art by programming the control system tofollow these rules and conditions.

In an embodiment each combustion chamber comprises an output controlledby a main exhaust valve 111. In an embodiment each combustion chambercomprises two outputs, one output being controlled by a main exhaustvalve 111 and one output being controlled by an auxiliary exhaust valve112. In an embodiment each combustion chamber comprises an open outputwhich is not controlled by valve. In an embodiment each combustionchamber comprises an input 101 for fuel. In an embodiment eachcombustion chamber comprises inputs 101, 102 for fuel and pressurizedair. In an embodiment each combustion chamber comprises inputs for fuel,pressurized air and steam. In an embodiment each combustion chambercomprises inputs for one or more of the following: fuel, pressurizedair, steam and water. The steam may be produced at least partially usingwaste heat of the combustion process of the system. In an embodiment,the steam is injected in the form of short, high pressure steam pulseswhich are injected into the combustion chamber between the expansionphases of the combustion process. In this embodiment, the exhaust valvesmay be omitted as the pressure and temperature conditions of thecombustion chamber are controlled with the steam pulse injections. In anembodiment steam is injected into combustion chamber and/or to theejector 12 and to the turbine 22. When both combustion chambers outputsare closed, steam can be injected directly into the ejector 12. In anembodiment, an ORC turbine or a Stirling engine can be used after theheat exchanger for cooling the exhaust gas and steam in a temperaturerange of about 200 degrees Celsius.

A combustion cycle in the system of FIG. 4 could have the followingsteps. First pressurized air is fed to the combustion chambers 10 a, 10b via air inputs 102 and fuel is fed to the combustion chambers 10 a, 10b via fuel inputs 101. In an embodiment fuels, especially gaseous fuels,can be compressed prior to feeding them into the combustion chamber.Fuels like for example carbon monoxide or hydrogen can be fed in apressure higher than atmospheric pressure to the combustion chamber. Thepressure in the combustion chambers is built up due to residue heatuntil the fuel in the combustion chambers ignites, for example at 2 to 3MPa pressure, and produces combustion products and more pressure. Thecombustion products and the pressure are released to the ejector 12 byopening the main exhaust valve 111 between a combustion chamber 10 a andthe ejector 12. In an embodiment the main exhaust valve is omitted andthe combustion products move freely to the ejector 12, in an embodimenta pressure wave supercharger replaces the main exhaust valve. Preferablythe combustion cycles in each combustion chamber runs with a phasedifference to the other combustion chambers so that the exhaust streamfrom the combustion chambers is steadier and less pulse-like. Thecombustion products flow from the combustion chamber to the ejector 12and from elector to turbine 22 through an output 113. At the same time,liquid water and/or water vapour i.e., steam can be injected to thecombustion chamber 10 a via inputs and thus improving the ventilation ofthe combustion products out of the combustion chamber. Preferably steamis injected into the combustion chamber in short pulses with high steampressure, for example ranging from several MPa to ten Mpa. The injectionof steam also helps to keep the pressure in an elevated level for anextended period of time as can be seen from FIG. 5. The injection ofwater and/or steam also lowers the temperature of the combustion chamberand facilitates temperature controlling. The combustion chamber may haveducts formed within combustion chamber cover for water and/or steamcirculation on exhaust side of the combustion chamber. The water and/orsteam can be injected into the ducts which water and/or steam thenperspirates from small apertures of the ducts. Heat is transferred fromthe exhaust side of the combustion chamber to the perspirating injectedwater and/or steam and the combustion chamber cools down. In anembodiment similar ducts and cooling system is used on the main exhaustvalve. The injection lowers the temperature of the main exhaust valve111 which can extend the lifetime of the main exhaust valve 111. Whenthe pressure in the combustion chamber and in the ejector has dropped,for example to 4 to 5 MPa, the main exhaust valve 111 is closed. One ormore of the valves may be electronically controlled for example via acontrol unit. In an embodiment the main exhaust valve 111 can be omittedwhen steam pulses are injected into the combustion chamber so the mainexhaust output is constantly open.

In an embodiment including the main exhaust valve, after closing themain exhaust valve 111 the ejector can be sprayed with liquid waterand/or water vapour i.e., steam via valve 103 which raise the pressurein the ejector 12, for example to 6.5 MPa. At a certain pressure in theejector 12, for example 6.5 MPa the main exhaust valve 111 of the secondcombustion chamber 10 b opens and releases combustion products to theejector 12 and from there to the turbine 22. At the same time thesecondary exhaust valve 112 of the first combustion chamber 10 a is keptopen to ventilate the residue combustion products from the firstcombustion chamber 10 a. The ventilation can be enhanced by introducingpressurized air or steam via the inputs 101, 102 to the combustionchamber. The secondary exhaust valve 112 may lead the residue combustionproducts to the turbine 22 via one or more second ejectors 14 a, 14 b.In an embodiment steam is injected into combustion chamber and/or to theejector 12 and to the turbine 22. When both combustion chambers outputsare closed, steam can be injected directly into the ejector 12. In anembodiment a single second ejector can comprise multiple inputs so thatit can be used with two combustion chambers. Once the first combustionchamber 10 a is ventilated and the pressure has dropped to asufficiently low level, for example to 2, 1, 0.5 or 0.2 MPa, thesecondary exhaust valve 112 is closed and the next cycle of thecombustion cycle can begin.

In an embodiment the second ejector 14 a, 14 b is arranged to receivemotive steam or motive gas via input 114. The motive gas is preferablypressurized water vapour for example in 6, 8 or 10 MPa pressure. Themotive gas is directed through the second ejector 14 a, 14 b anddischarged to the ejector 12 via valve 104. When the motive gas goesthrough the second ejector it creates a suction effect drawing residuecombustion products from a combustion chamber 10 a, 10 b when outputvalve 112 connecting the combustion chamber to the second ejector isopen. The valve 104 is preferably a control valve. The throughput and/oropening direction of the valve 104 can be adjusted. In an embodiment allexcess steam produced within the system can be fed to the turbine viathe valve 104 and/or the second ejector 14 a, 14 b.

In an embodiment a back flow from the turbine 22 using an intermediatesteam tapping can be introduced to a third ejector. The back flow or theintermediate steam from the turbine may comprise steam or combustionproducts or a mixture of steam and combustion products which areintroduce to the third ejector. The pressure of the intermediate steamat the third ejector is raised to a sufficient level by using valves andintroducing gas such as water vapour to the third ejector. The steam andthe combustion products increase the volume of the gas and decrease thetemperature of the gas. The mixture of gases is introduced from thethird ejector to the ejector 12 for example via the second ejector 14 a,14 b and valve 104, or to some other input valve of the system. In anembodiment, an output using an intermediate steam tapping can also beintroduced right after the heat exchanger.

In an embodiment the turbine is arranged to rotate a by-pass fan in anaviation application for example replacing turbofan engines ofcommercial airplanes. In an embodiment the system comprises an oxygentank connected to the combustion chamber and controlled with a valve.The combustion chamber can be used as a combustion chamber of rocketengine using rocket fuel from the fuel tank and oxygen from theatmosphere in the lower atmosphere so that the oxygen from the oxygentank can be used in the upper atmosphere where the amount of oxygen isnot sufficient for the combustion.

FIG. 5 illustrates time dependence of pressure in a system according toan embodiment. As the combustion cycle causes the pressure to changewithin the system in rather broad range, the turbine 22 does not receiveoptimal input unless the system in controlled in a time-dependentmanner. Preferably all the inputs 101, 102, 103, 104 are controlled intime-dependent manner to keep the output 113 to the turbine in optimalpressure. Without any other time-dependent inputs than fuel and air, theoutput to the turbine would look like the curve 200 in FIG. 5. In thebeginning of the combustion cycle the pressure builds up quickly peakingjust before the main exhaust valve 111 is opened which quickly lowersthe pressure as the combustion products flow through the turbine. Now ifthe combustion chamber is injected with liquid water and/or water vapourimmediately after the main exhaust valve 111 is opened, the pressurewould not fall as quickly because the liquid water would evaporate andthe vapour would heat up due to residue heat of the combustion chamberand thus the injection would lessen the impact of opening the mainexhaust valve 111. In a similar manner, once the main exhaust valve 111has been closed, the ejector can be sprayed with liquid water and/orwater vapour i.e. steam via valve 103 which raise the pressure in theejector 12 thus raising the output pressure to the turbine. The amountof liquid water, steam and air is controlled in a time-dependent mannerin order to prevent the output to the turbine from dropping too much.Keeping the output to the turbine in an elevated and relatively constantlevel has a significant impact on the efficiency of the system. Theturbine can be driven in optimal operating range most of the time with arelatively constant output whereas the turbine can not make the most outof sparse, short bursts.

The output to the turbine can be maintained in an elevated level withthe injection of water, steam and air. This elevated level isillustrated with dashed line 201 in FIG. 5. However, a lot of steam andair is needed to maintain such a high pressure if the main exhaust valveis omitted or kept constantly open. If the injection of steam is in theform of very short and high pressure pulses, the main exhaust valve canbe omitted thus simplifying the system and increasing its reliability.Curve 202 represents the pressure level during a combustion cycle whenthe injections are in the form of short steam pulses. The short steampulses can maintain the average pressure at a high enough level that themain exhaust valve is not necessary. The short steam pulses may havepeak pressure higher than the pressure pulse caused by the combustion.In an embodiment of e.g. two combustion chambers, short steam pulses canbe fed to the system (e.g. to the first combustion chamber) after fuelis ignited and combustion products expelled from the first combustionchamber. The feeding of steam pulses can be continued while an exhaustvalve of the second combustion chamber is closed. During that time anyresidue steam and combustion products are flushed from the secondcombustion chamber. The second combustion chamber is flushed with aninput of compressed air which flows through e.g. a secondary exhaustvalve 112 which then conveys the air and the residues to e.g. lowerpressure turbine. After the flushing the second combustion chamber isfilled with compressed air, fuel is injected to the second combustionchamber and the mixture ignites or is ignited. After the fuel is ignitedand combustion products expelled from the second combustion chamber,short steam pulses can be fed to the system (e.g. to the secondcombustion chamber) while the exhaust valve of the first combustionchamber is closed, the first combustion chamber is flushed, filled andignited like the second combustion chamber earlier, and so on. Thisenables high enough pressure for efficient use of the turbine throughoutthe process.

In an embodiment the pressure within the ejector 12 is kept always overfor example 2, 3, 4 or 5 MPa. In an embodiment the amount of injectedwater, steam and air and point of time at which those are injected aredetermined based on measured quantities of the system. Such measuredquantities can be for example temperature, pressure, humidity, gascomposition, state of a valve or some other process quantity. Saidquantities can be measured with e.g. sensors. In an embodiment theamount of injected water, steam and air and point of time at which thoseare injected are determined based on the phase of the combustion cycle.The time dependent injection of water, steam also increases thereliability of the turbine 22 by controlling the temperature of the gaswhich is introduced to the turbine 22. The injection of water and steamlowers the average temperature of the gas introduced to the turbine andtherefore it allows for higher pressure (and thus higher temperature) tobe used in the combustion chamber.

In an embodiment the power generator system is used together with aturbocharged combustion engine. The power generator system can feedsupplemental energy to the turbocharger of the combustion engine whichcan be beneficial in three ways. First, the pressure ratio of theturbocharger can be controlled regardless of running speed (rpm) and/orload of the combustion engine. This is beneficial in controllingemissions and pollutants of the combustion engine and it also improvesload response of the combustion engine. Also the compressor belonging tothe pulse turbine system can be used for supplying the input of air.Second, the system may provide output of mechanical power from a shaftof the turbocharger or the turbine of the power generator system whichprovides an additional power which depends on the amount of additionalenergy fed to the system. Third, the power generator system can use atleast part of the exhaust flow of the combustion engine s an energysource. Also the input of air to the combustion chamber can be arrangedwith air supply system of the combustion engine as such or supplementedwith additional air supply pump, such as Roots blower. Also a compressorof the power generator system can be used for supplying the input ofair.

It will be obvious to a person skilled in the art that, as thetechnology advances, the inventive concept can be implemented in variousways. The invention and its embodiments are not limited to the examplesdescribed above but may vary within the scope of the claims.

The invention claimed is:
 1. A power generating system having a turbinein connection with one or more compressors for converting energy fed tothe turbine into mechanical energy of a power shaft and to compress air,a combustion chamber arranged to receive fuel from a fuel tank and thecompressed air to initiate a combustion process and output combustionproducts into the turbine for rotating a rotor of the turbine andthereby rotating the power shaft, one or more fuel input valves forproviding the fuel to the combustion chamber, one or more compressed airinput valves for providing the compressed air to the combustion chamber,and a control unit for controlling the one or more fuel input valves andthe one or more compressed air input valves in order to control thecombustion process, where the power generating system further comprisesan air chamber configured to be cooled with a fluid and arranged toreceive the compressed air from the one or more compressors, heat thecompressed air and exhaust the heated compressed air to the combustionchamber.
 2. A power generating system as claimed in claim 1, where thepower generating system further comprises: a heat exchanger in thermalinteraction with the combustion products exhausted from the turbine fortransferring heat from the exhausted combustion products into steam, oneor more steam input valves for providing the steam to the turbine, wheresaid one or more steam input valves are controlled in order to generatea time-dependent steam injection into the turbine.
 3. A power generatingsystem as claimed in claim 2, where the power generating system furthercomprises: a steam tank for accumulating the steam, a condenser forcondensing the steam into water, a water tank for accumulating thewater, and a pump for pumping the water from the water tank to the heatexchanger for vaporizing the water into the steam which is arranged toflow into the steam tank.
 4. A power generating system as claimed inclaim 1, where the combustion chamber is arranged to work in cyclescomprising a compression phase and an expansion phase.
 5. A powergenerating system as claimed in claim 1, where the combustion chamber isarranged to work in two alternating cycles wherein the first alternatingcycle is a combustion cycle in which the fuel is fed to the combustionchamber and the second alternating cycle is a cooling cycle in which asecond fluid is arranged to flow through the combustion chamber forcooling the combustion chamber.
 6. A power generating system as claimedin claim 1, where the power generating system comprises an electricgenerator driven by the power shaft for generating electric power.
 7. Apower generating system as claimed in claim 1, where the fuel used inthe power generating system is one of the following group: hydrocarbonfuel, diesel, gasoline, ethanol, natural gas, liquid natural gas andmixture of hydrogen and carbon monoxide.
 8. A power generating system asclaimed in claim 1, where the air chamber is arranged to accumulate thecompressed air and provide the compressed air to the combustion chamber.9. A power generating system as claimed claim 1, where the control unitis arranged to control one or more pulse input valves for generating aplurality of steam injection pulses into the power generating systemwithin a single combustion cycle.
 10. A power generating system asclaimed in claim 1, where the one or more fuel input valves and the oneor more air input valves are arranged to control the combustion processto match a frequency of specific gas oscillations.
 11. A method forgenerating power comprising: providing an input of compressed air to acombustion chamber, providing an input of fuel to the combustionchamber, providing an output of a stream of combustion products and thecompressed air from the combustion chamber to a turbine for producingpower, operating one or more compressors for compressing the compressedair from the combustion chamber, and controlling the input of compressedair and the input of fuel to the combustion chamber for running acombustion process cycle in the combustion chamber, wherein saidcontrolling of the inputs of compressed air and fuel is time-dependent,accumulating the compressed air from the one or more compressors to anair chamber, cooling the air chamber with a fluid, heating thecompressed air inside the air chamber, exhausting the heated compressedair from the air chamber into the combustion chamber.
 12. A method asclaimed in claim 11, where controlling the input of compressed air andthe input of fuel to the combustion chamber such that the combustionprocess cycle matches a frequency of specific gas oscillations.
 13. Amethod as claimed in claim 11, where the method further comprises:extracting heat from the combustion process cycle for producing andheating steam, and providing and controlling a pulsed input of the steamto the turbine.
 14. A method as claimed in claim 11, where saidtime-dependent controlling of the inputs of compressed air and fuelcomprises creating steam or water pulses into the combustion chamber.15. A method as claimed in claim 11, where the method comprises a stepof controlling an ejector input valve for creating steam or water pulsesto an ejector between the combustion chamber and the turbine.
 16. Amethod as claimed in claim 11, where the method comprises a step offlushing residue steam and the combustion products from the combustionchamber while a main exhaust valve is closed wherein the combustionchamber is flushed with a second input of compressed air which flowsthrough a secondary exhaust valve.
 17. A power generating system havinga turbine in connection with one or more compressors for convertingenergy fed to the turbine into mechanical energy of a rotatable powershaft and to compress air a combustion chamber arranged to receive fuelfrom a fuel tank and the compressed air to initiate a combustion processand output combustion products into the turbine for rotating a rotor ofthe turbine and thereby rotating the rotatable power shaft, one or morefuel input valves for providing the fuel to the combustion chamber, oneor more compressed air input valves for providing the compressed air tothe combustion chamber, and a control unit for controlling the one ormore fuel input valves and the one or more compressed air input valvesin order to control the combustion process, where the power generatingsystem further comprises an air chamber arranged to receive thecompressed air from the one or more compressors, heat the compressed airand exhaust the heated compressed air to the combustion chamber, andwhere the air chamber further comprises one or more ducts within the airchamber for flowing ambient or heated fluid in order to heat or cool thecompressed air inside the air chamber.
 18. A power generating systemhaving a turbine in connection with one or more compressors forconverting energy fed to the turbine into mechanical energy of arotatable power shaft and to compress air a combustion chamber arrangedto receive fuel from a fuel tank and the compressed air to initiate acombustion process and output combustion products into the turbine forrotating a rotor of the turbine and thereby rotating the rotatable powershaft, one or more fuel input valves for providing the fuel to thecombustion chamber, one or more compressed air input valves forproviding the compressed air to the combustion chamber, and a controlunit for controlling the one or more fuel input valves and the one ormore compressed air input valves in order to control the combustionprocess, where the power generating system further comprises multipleair chambers each arranged to receive the compressed air from the one ormore compressors, heat the compressed air and exhaust the heatedcompressed air to the combustion chamber, wherein each of said multipleair chambers is arranged to receive the compressed air from a specifiedcompressing stage of said one or more compressors, heat the compressedair and exhaust the heated compressed air to the combustion chamber inpredetermined order.
 19. A power generating system having a turbine inconnection with one or more compressors for converting energy fed to theturbine into mechanical energy of a rotatable power shaft and tocompress air, a combustion chamber arranged to receive fuel from a fueltank and the compressed air to initiate a combustion process and outputcombustion products into the turbine for rotating a rotor of the turbineand thereby rotating the rotatable power shaft, one or more fuel inputvalves for providing the fuel to the combustion chamber, one or morecompressed air input valves for providing the compressed air to thecombustion chamber, and a control unit for controlling the one or morefuel input valves and the one or more compressed air input valves inorder to control the combustion process, where the power generatingsystem further comprises an air chamber arranged to receive thecompressed air from the one or more compressors, heat the compressed airand exhaust the heated compressed air to the combustion chamber andwhere the power generating system further comprises an air tank foraccumulating the compressed air received from the one or morecompressors and for providing the compressed air to the combustionchamber.